One of the most significant aerospace advances in the early years
of the 21st Century has been the successful operational introduction of
US armed drone aircraft in the ground attack role. Above all, such
systems offer the long-term prospect of reducing aircrew losses in
high-risk missions such as defence-suppression (and in cross-border
strikes of dubious legality).

Because they are generally much smaller and thus less easily
detected than their manned equivalents, drones allow sensors to be taken
closer to the target and maintained there for significant periods.
Proximity also allows economies through the use of low-cost direct
attack munitions, rather than expensive standoff weapons. Drones may
well offer advantages over manned aircraft in the use of directed energy
(DE) weapons, i.e., high-power lasers and microwave devices. Drones will
require less shielding around such weapons, and target proximity will
reduce the emitted power demand.

Against such advantages must be reckoned the increased possibility
of fratricidal incidents and collateral damage, since the drone is
controlled by a remote operator, quite possibly in another country. The
'weaponised' drone now stands where the manned aircraft stood
just over a century ago, and there will inevitably be teething problems
before anything like the same level of dependability is achieved in
ordnance delivery.

Test-firings of the 48 kg laser spot-homing Lockheed Martin AGM-114
Hellfire from a 1040 kg General Atomics MQ-1L Predator-A began on 16
February 2001, this trial series producing 12 successes from 16 rounds.
The first operational engagement with this combination was carried out
by the CIA in Afghanistan in October 2001. It was followed on 3 November
2002 by a CIA mission in Yemen, in which a Predator operating from
Djibouti employed a Hellfire to destroy a four-wheel drive vehicle
believed to contain six terrorists.

Some commentators glossed over the fact that the Hellfire
(developed to destroy a main battle tank in a supersonic attack at long
range) represents an uneconomic way to deal with a nonarmoured and
undefended vehicle. The Hellfire/Predator combination has also been used
in Afghanistan to engage even softer targets, such as small groups of
personnel. Considerable efforts have subsequently been directed at
finding or developing weapons that are not only light (and thus are
easily carried by smaller aircraft) but are also substantially less
expensive than the Hellfire, while retaining effectiveness against a
broad target set, under a useful range of environmental conditions.

History

Although armed drones first hit the headlines in Afghanistan, they
existed as far back as the Vietnam War, in the form of the US
Navy's shipborne torpedo-carrying Gyrodyne Dash (Drone
Anti-Submarine Helicopter) or QH-50C/D. On a similar timescale, armament
trials were carried out with the US Air Force's AQM-34 Firebee, a
target drone converted for reconnaissance duties.

Although Vietnam-era trials demonstrated the technical feasibility
of delivering ordnance from drones, this was concluded to represent only
a long-term possibility. Out of 746 QH-50s built for the Dash project,
411 were lost in accidents. The programme was finally terminated in
1970. There was evidently a long way to go before drones could be relied
upon to fulfil the attack mission.

In the fixed-wing field, the fighter pilot lobby drowned out any
calls for money to be diverted to armed drones. It was only later, after
the effectiveness of Soviet-developed air defence systems was fully
appreciated, that there were demands to explore the potential of
uninhabited aircraft for the most dangerous missions.

When the need for a drone-compatible air-to-ground weapon arose in
the 'Global War on Terrorism' in the aftermath of nine-eleven,
the emphasis was on light weight, precise delivery, effectiveness
against a wide range of targets (including fortifications and mountain
caves) and fire-and-forget capability. The 48-kg laser spot-homing
Lockheed Martin AGM-114M/K Hellfire was the obvious choice, although
remotely controlled firings from a Predator have been severely limited
by its seeker's eight-degree field of view.

In the case of the new AGM-114P ('P' for Predator)
version, recently developed by the US Army Redstone Arsenal in Alabama,
the weapons engagement zone (WEZ) has been greatly increased by
extending this look-angle to 90 degrees. This version also has an
improved gyroscope and modified targeting software, making possible
engagements at large off-boresight angles. They also allow the maximum
release altitude to be increased from 10,000 to 25,000 ft, thus
eliminating the need for the Predator to descend prior to firing. The
AGM-114P was cleared for service in early 2005.

The Hellfire is evidently seen as the principal weapon for the US
Army's Extended-Range/Multi-Purpose (ERMP) drone, which is to carry
one on each of four pylons. This ERMP requirement is to be fulfilled by
the General Atomics Warrior, a 1360-kg Thielert heavy fuel engine
version of the Predator-A, with slightly larger 17-metre wings, four
weapon pylons with a total capacity of 227 kg and modernised avionics.
The Army plans to acquire eleven Warrior systems, each with twelve air
vehicles. The Warrior will have an endurance of over 30 hours and a
ceiling of 29,000 ft. The first delivery is due in 2007, leading to
initial operational capability in FY2009.

At the 2005 Paris Air Show, General Atomics exhibited a model of
the much heavier (4765 kg), turboprop-powered MQ-9A Predator-B with a
pair of four-Hellfire arrays, and two Raytheon AIM-9 Sidewinders for
self-defence. The US Air Force has subsequently revealed that YQM-9A
prototypes have been deployed for operational use with clearance for two
225 kg GBU-12 Paveway II laser-guided bombs. These are to be followed by
four interim-standard Predator-Bs with the General Atomics Lynx radar
and clearance for the GBU-12, 225 kg Boeing GBU-38 Jdam, AGM-114
Hellfire and one other air-to-ground missile.

The uneconomic use of Hellfires against relatively trivial targets
in Afghanistan has highlighted the need for a less expensive complement.
One very light option is the 2.4 kg Spike missile, which was originally
developed by the US Naval Air Warfare Center at China Lake, California,
and more recently by DRS Technologies. The Spike was conceived as a
cheap ($ 4000) surface-to-surface guided weapon, to complement the US
Marine Corps' $100,000 (class) Raytheon FGM-148 Javelin anti-armour
missile. Intended to deal with non- or lightly armoured vehicles, the
Spike employs electro-optical guidance with a contrast-lock facility
giving fire-and-forget operation. For nighttime use a laser seeker is
proposed. The Spike has a range of about 3.2 km.

The DRS-built Spike is one of several weapons that have been tested
from the same company's 147 kg Sentry HP drone by the US Air Force
UAV Battlelab at Eglin AFB, Florida. Other missiles fired from the
Sentry are believed to have included the fibre-optically guided Rafael
Spike-ER, a completely different and far more potent weapon. Weighing 33
kg in its launch tube, the Israeli missile has a range of eight
kilometres and can be locked on to the target after launch. It can also
penetrate 1000 mm of rolled homogeneous armour. The Spike-ER, which has
also been fired from the 330 kg Sagem Sperwer, is rumoured to have been
used operationally from Israeli drones against terrorist targets in the
Gaza Strip.

The operational potential for armed drones further benefits from a
range of parallel weapon developments for other purposes. For example,
the US Army has vast stocks of the helicopter-launched 12.5-kg General
Dynamics Hydra 70 unguided rocket projectile, which would be far more
cost-effective if given laser spot-homing guidance and control kits.
This APKWS (Advanced Precision Kill Weapon System) programme has been
thrown open to competition in its second phase (APKWS-II), in which GD
is teamed with BAE Systems, Raytheon with Aerojet, Goodrich and EFW.

Another US weapon development applicable to drones is the SDB (Small Diameter Bomb), which is aimed at achieving the penetration
capability of a 900-kg BLU-109 bomb, but as an advanced technology
munition that would fit inside the small internal bay of a stealth
aircraft. The first phase was won by Boeing in 2003 with the 130-kg
GPS-guided Increment I or GBU-39, which was designed to destroy fixed
targets of known location.

The Increment II version of the SDB is to deal with moving targets
in any weather, which requires a multi-mode seeker. In August 2005 this
SDB-II programme was thrown open to competition. This led to Boeing
teaming with Lockheed Martin, thus benefiting from seeker work on the
latter's JCM (Joint Common Missile), Lam (Loitering Attack Missile)
and Smacm (Surveilling Miniature Attack Cruise Missile). Other
contractors with the necessary seeker experience are Northrop Grumman
and Raytheon. Raytheon is partnered with Lockheed Martin on the US Army
NetFires Nlos-LS (Non-Line-Of-Sight Launch System) programme, and is
leader on its Pam (Precision Attack Missile) component, which--like the
Lam--has a multimode seeker. With a wing-kit, the SDB-II is expected to
provide a range of around 75 km from a 40,000 ft release.

It may be noted that, since they each weigh less than 50 kg, both
the Lam and the Pam (designed to be fired from a US Army 16-tube
vertical launch unit) may well be employed from drone aircraft. The
Raytheon Pam is primarily an anti-armour weapon powered by an Aerojet
variable-thrust rocket motor and has a range of around 40 km. It is
equipped with an uncooled imaging-infrared sensor and laser seeker. An
improved version (iPam) is credited with a range of 85 km. The Lockheed
Martin Lam has a miniature turbojet engine and extendable wings, making
possible about 30 minutes on station at 70 km distance. It is equipped
with a ladar seeker and has an automatic target recognition facility.
The Raytheon Precision Attack Air-to-Surface Missile (Paasm), derived
from the Pam, was test-fired from a Bell UH-1 on 13 December 2005.

Another loitering missile in the 50 kg category is the projected
Boeing Area Dominator, which would patrol for up to 42 hours at an
altitude of 3500 ft and dispense up to eight submunitions. Its advanced
technology features include a StarVision Technologies VisNav sensor
system, to make possible autonomous in-flight refuelling.

Submunitions

Another area of weapons development from which drones may benefit
is the smart submunition, intended to allow a single artillery shell or
rocket (or an airdropped dispenser) to destroy multiple armoured
vehicles. Several submunition designs make use of a spinning descent to
give a fixed sensor a conical scan-pattern, the sensor launching a
highly directional warhead upon detecting a target.

The best-known example is probably the 3.4 kg Textron Systems
Skeet, which is normally dispensed spinning from the company's
29-kg, four-round BLU-108/B. The submunition is now also available in
the form of Textron Systems' 4.5 kg Selectively-Targeted Skeet,
which has a Samara wing to provide auto-rotation. Another important
spinning, sensor-fuzed submunition is the 6.5 kg Bofors Defence/ Giat
Bonus.

Textron Systems has recently unveiled the Claw (Clean Lightweight
Area Weapon), which has the same external dimensions and weight as the
BLU-108, presumably to give the same release characteristics and thus
minimise clearance tests. It has a single insensitive munition warhead
with rings of thermobaric material (zirconium) that produce blast,
fragmentation and incendiary effects over a wide area. It has
self-destruct and timed de-activation facilities.

With US Air Force funding Textron Systems is developing a Guided
Dispenser System to carry multiple submunitions on drones such as the
RQ-5 Hunter and MQ-1L Predator-A. In the context of store carriage for
drones it may be noted that at the 2005 Paris Air Show EDO launched the
Sabre family of non-pyrotechnic carriage and release systems for
combined loads up to 590 kg. The twin-station Sabre weighs only 13.5 kg
and the triple-store version 18.7 kg. The unit can eject stores at up to
3.66 m/sec. Stara Technologies claims to be the sole developer of
miniaturised GPS-guided parafoils for the precision delivery of
lightweight sensors and weapons.

In 2004 two BLU-108s were test-dropped from the DRS Sentry HP drone
mentioned earlier, and six of their eight Skeets hit targets. In early
2006 the US Air Force plans to release two BLU-108s and two Claws from
an MQ-1L Predator-A. Other submunitions with drone potential include the
20 kg Northrop Grumman Bat, which for drone use is carried in a tube and
ejected forwards by a gas-driven piston. In late 2002 the first Bats
were dispensed in tests from a 725-kg modified Northrop Grumman RQ-5A
Hunter. The Army has ordered 18 examples of the weapons-capable MQ-5B
version, which has a heavy fuel engine, a longer-span 'wet'
wing and a maximum weight of 816.5 kg. The MQ-5B can carry 60 kg under
either wing.

The Bat has now evolved into Viper Strike, which employs laser
spot-homing. A small number of Viper Strikes have been deployed by the
US Army to Iraq with a pair of modified Hunters. Northrop Grumman is
reportedly making efforts to reduce the weight of the Viper Strike to
11.3 kg, to make it suitable for the 168 kg AAI RQ-7B Shadow 200.

A much heavier submunition is the 45-kg Lockheed Martin Locaas
(Low-Cost Autonomous Attack System), which is capable of armed
reconnaissance missions. It has a multi-mode warhead that can be
detonated as a long-rod penetrator, an aero-stable slug or as fragments.
The powered Locaas (now under development) has a 0.45-kN Technical
Directions T45G turbojet, providing an endurance of up to 30 minutes. It
has satellite/inertial mid-course navigation and a ladar seeker that can
identify the target and determine the aim-point and warhead mode.

The advent of 'ordnance-trucks' such as the 4765-kg
General Atomics MQ-9B Predator-B makes possible multiple carriage of
heavier weapons, such as the 130-kg SDB, and the 225 kg (class)
GPS-guided Boeing GBU-38 Jdam and laser/GPS-guided Raytheon/Lockheed
Martin GBU-12 Paveway II bombs.

In the air-to-air missile category, the majority of drones will be
restricted to lightweight weapons such as the 11.5-kg KBM Igla and
Raytheon Stinger, and the 18.7 kg MBDA Mistral. Heavier designs such as
the Predator-B and Elbit Hermes 450 will open the field to missiles like
the 85-kg Raytheon AIM-9X and the same company's 156-kg AIM-120.

UCAVs

Paving the way for production Ucavs (Unmanned Combat Air Vehicles),
the Boeing X-45A and Northrop Grumman X-47A began flight trials in May
2002 and February 2003 respectively. In October 2003 these technology
demonstration programmes were merged into the J-Ucas (Joint Unmanned
Combat Air System), the management of which was transferred on 1
November 2005 from Darpa to a joint office at Wright-Patterson AFB.

Providing much more capability than current armed drones, J-Ucas
air vehicles will eventually provide first-day-of-war Sead missions
supporting manned strike packages, and later armed surveillance. Spiral
One consists of larger, stealthy derivatives of the present
demonstrators, the 16,555-kg Boeing X-45C and the 20,865-kg Northrop
Grumman X-47B both being scheduled to fly in 2007. The X-45C will have a
General Electric F404-GE-102D turbofan and the X-47B a Pratt &
Whitney F100-PW-220U.

Although the J-Ucas is intended to lead to a bi-service product, it
appears likely that the requirements of the two services will diverge.
The US Air Force seems to be considering a much heavier high-speed
global strike system, while the US Navy is restricted by
carrier-compatibility to a lighter weight, and is reportedly more
interested in long endurance, rather than rapid reaction over long
distances.

Despite the inter-service fighting that continues to plague US
military equipment programmes, it appears inevitable that America will
continue to lead in the development and employment of armed drones.
Europe lacks the inclination to spend large sums on the Ucav concept,
but France, Greece, Italy, Spain, Switzerland--and now Sweden, which
announced on 20 December 2005 its intention to officially take an active
part in the programme--are to co-operate on a technology demonstration
programme in which Hellenic Aerospace Industries, Alenia Aeronautica,
Eads-Casa, Ruag and Saab will act as subcontractors to Dassault Aviation
(see Drone Update, Armada 6/2005, page 59 for full details). The
resulting five-tonne class Neuron is scheduled to fly in 2010.

Other European companies interested in what is clearly a long-term
growth market include Eads Military Aircraft, which has begun studies of
an unmanned reconnaissance air vehicle demonstrator, that will boast an
endurance of up to six hours at 40,000 ft.

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